US 20030135856 A1
A channel map in an electronic television program guide system that includes channel numbers and alphanumeric channel labels is updated. The tuner in the system is tuned to a channel number of a television channel that is included in the channel map. Data is extracted from the television signal that includes an alphanumeric label for the tuned television channel. The channel mapis revised according to the alphanumeric label for the tuned television channel if the alphanumeric label in the extracted data for the tuned television channel does not correspond with the alphanumeric channel label stored in the channel map for the tuned television channel.
1. A method of updating a channel map in an electronic television program guide system that includes channel numbers and alphanumeric channel labels comprising:
tuning to channel number of a television channel that is included in the channel map;
extracting data from the television signal including an alphanumeric label for the tuned television channel;
revising the channel map according to the alphanumeric label for the tuned television channel if the alphanumeric label in the extracted data for the tuned television channel does not correspond with the alphanumeric channel label stored in the channel map for the tuned television channel.
 This application is a continuation of U.S. patent application Ser. No. 09/526,306, filed Mar. 15, 2000 which claims priority of U.S. Provisional Patent Application No. 60/124,476, filed on Mar. 15, 1999, the disclosures of which are incorporated fully herein by reference.
 The present system and method of channel map correction in an EPG uses a television broadcast system as described in International Application No. PCT/US96/17920, an electronic program guide (“EPG”) as described in U.S. application Ser. No. 09/120,488, a method and apparatus for transmitting and downloading setup information as described in International Application No. PCT/US97/00739 which are incorporated into this application by reference. Appendix A describes the method of using XDS call letter data to correct channel maps. Appendix A are incorporated into this application by reference.
 In a television system capable of receiving television programs from various programming sources, e.g. cable, antenna, or satellite, two or more sources may carry an identical television station (e.g. XNBC is carried by both cable and satellite). Thus, in presenting program listings of all the sources in a single guide format, it is desirable to delete duplicative stations to conserve memory and avoid cluttering of the guide with duplicative program information.
 According to one aspect of the invention, a channel map in an electronic television program guide system that includes channel numbers and alphanumeric channel labels is updated. The tuner in the system is tuned to a channel number of a television channel that is included in the channel map. Data is extracted from the television signal that includes an alphanumeric label for the tuned television channel. The channel mapis revised according to the alphanumeric label for the tuned television channel if the alphanumeric label in the extracted data for the tuned television channel does not correspond with the alphanumeric channel label stored in the channel map for the tuned television channel.
 The objects, advantages and features of this invention will become more apparent from a consideration of the following detailed description and the drawings in which:
FIG. 1 is a schematic block diagram of a television receiver for practicing the invention;
FIG. 2 illustrates a typical EPG screen on a televison monitor at the receiver of FIG. 1;
 International application Ser. No. PCT/US97/00739 discloses a television system which receives television transmission from either over-the-air (“OTA”) broadcast, cable ready signals, or cable box signals. It also describes a way to transmit and download setup information for that television system. The system described there automatically generates a channel map corresponding to the source of the television transmission. A channel map relates television station call letters to their respective channel allocations.
 In a preferred embodiment, the system and method disclosed in International application Ser. No. PCT/US97/00739 is extended to handle the situation where a single television system is capable of tuning to multiple television sources, including satellite and digital sources, and receives a channel map from each of the sources. A single television guide is then created based on the channel maps. This guide tells you how to find a channel, regardless of its source. It is desirable to do this in a way that eliminates redundant listings, and conserves memory.
 A channel map will be generated for each program source. Initially the viewer inputs the sources of programming available to his television, such as a cable subscription and/or a DSS unit. The user also inputs their zip code. Zip code allows transmission of program line ups that are available in an area to be picked up by the subscriber's receiver.
 The user, through a remote control unit, issues a set up command, which is transmitted to a main micro controller in the television system which initiates a auto set up procedure telling program stored in internal memory that will include declaring a channel map.
 The channel mapping program accesses an extended channel map selection packet. A channel map ID based on the inputted zip code is identified. A channel map corresponding to the identified channel map ID is then downloaded into the system.
 Each local host station provides channel mapping information to the viewer. This is done by transmitting an extended channel map (“XCM”) packet with television channel allocations (receiving channel numbers) corresponding to Channel ID. The XCM packet also transmits a “channel map type” field that identifies the multiple programming sources. This field has several attributes: dual (A/B) trunk, digital signal, and system type. If the dual trunk bit is clear, the system is single trunk (or other feed such as OTA or DSS). If the digital signal bit is clear, the signal is analog. The system type attribute allows specification of the type of source (e.g. OTA=0, cable=1, and satellite=2).
 The channel ID is used to select the appropriate guide channel(GCH)-to-call-letter mapping from the extended source map (“XSM”) packet. Information in the XCM and XSM packets are then merged to create a lineup. An example of a source map, a channel map, and a finalized lineup is shown below.
 After channel maps of all the sources have been generated, the system merges the channel maps into a single merged channel map. However, channel maps frequently change. To facilitate these changes network name (affiliation) and call letters (station ID) from the channel information class of the XDS data corrects the lineups automatically. An exemplary embodiment of the invention consists of firmware that stores a list of channel names in its source map. The firmware also stores a list of all receiver channels on which the channels are received in the channel map. As with the source map the channel map is an array, of which a channel ID is an index. The algorithm for updating the channel map is given in detail in Appendix A.
 The first step is to initiate a search. This is done by pointing the data tuner to a channel for which the XDS data is to be examined. The XDS feed for a given station is examined for call letters or network name. When these appear the Channel map stored in the viewers location is queried. If the station on which the channel is stored differs from the one on the XDS feed, a full search is scheduled for a non download period.
 The next step is to scan the channel map. This must be done between downloads so that sufficient time for a search is available.
 The receiver channel from the channel map for any channels in the source map whose call letters match those found in the XDS data, is compared to the current channel. If they match, nothing is done. If they do not match a check is later made to determine if this is a split channel. If not a split channel the receiver channel found in the channel map is checked for XDS data.
 Data collected from the original channel can lead to 3 cases which must be analyzed, as described in Appendix A. If this original channel has the same data as the scan channel, no change is made. If no data or different XDS data is present here, on the original channel, the channel map will be corrected. However if it is determined that the user has edited this channel a correction will not be made.
 In an alternate embodiment it may be desirable to collect XDS data from all channels if the call letter data on the scan channel does not match the channel map.
 Additionally this embodiment is designed to support digital television. In digital television, a television station can divide its bandwidth so that multiple sub channels are available. For example it is desirable to use the full bandwidth for movies or other transmissions that need the highest image quality. For news shows, for example, a high quality picture might not be necessary, or desired. If this is the case the channel can be divided to show several programs on sub channels. The number of sub channels can expand and contract during the day. It is desirable to list these sub channels in the guide.